Wireless process control devices, such as wireless valve positioners, can facilitate control of valves and other equipment in hard-to-reach places or where a wired solution is not cost-effective or practical. However, the process control industry has been slow to adopt such wireless process control devices due to concerns related to the lifetime of batteries that power the wireless process control devices. If a battery powering a valve positioner is drained of power, the valve controlled by the positioner will go into a fail safe mode and will cease to be controlled.
Although improved battery technology may increase the lifetime of batteries, the fact remains that power sources powering wireless process control devices need to be replaced at certain times during the operation of the wireless process control devices. Even if such a replacement occurs before a battery runs out of power, the replacement of one battery with another battery still can cause an interruption in the operation of the wireless process control device.